Browsing the preprocessor section of the standard today I stumbled
across the following in 16.8(1) - Predefined macro names

"__STDC__
Whether __STDC__ is predefined and if so, what its value is, are
implementation-defined."

This seems to place no restriction on this name whatsoever, so I wonder
why it is explicitly in the standard at all?

--
AlisdairM

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"Alisdair Meredith" <alisdair.meredith@uk.renaultf1.com> wrote in message news:3EAFB6CE.754CAFE5@uk.renaultf1.com...
> Browsing the preprocessor section of the standard today I stumbled
> across the following in 16.8(1) - Predefined macro names
>
> "__STDC__
> Whether __STDC__ is predefined and if so, what its value is, are
> implementation-defined."
>
> This seems to place no restriction on this name whatsoever, so I wonder
> why it is explicitly in the standard at all?

It's a C thing.   It is set to 1 to indicate a standard conforming C implementation
(from the original C90 standard).   Whether it is present or absent in a C++
compilation is up to the implementation.

Note unlike the __cplusplus flag, it doesn't convey the version of the standard.
They have a separate value for that (which didn't appear until the second version
of the standard).


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